The present invention relates to a pressure tank, particularly for a hot-water heater, with a water-tight synthetic inner liner and a glass fiber wrapping which reinforces it. The glass fiber wrapping is fixed to individual locations on the liner by means of synthetic material located at these locations and/or is held to the liner by means of a foamed synthetic layer placed around the glass fiber wrapping.
With such pressure tanks, the inner liner is conventionally made by the blowing method and as such is not suited for accomodating greater water pressures. It therefore has been proposed that the liner be wrapped with glass threads (rovings) which are synthetically saturated throughout their entire length. This results in an undesirable odor in the water used which arises from the diffusion of the synthetic, e.g., styrol containing resin, which saturates the glass threads, and which develops during hardening in the liner. In addition, the complete saturation of the glass fiber wrap with synthetic material is expensive.
In the area where the glass fiber wrapping is not embedded in synthetic material, it tends to rot. This can be attributed to the steam diffusion which takes place through the walls of the liner. One method for preventing rotting of the glass fibers is to apply a steam tight coating to the liner. Obviously, this requires an additional operation in the manufacture of the pressure tank.
It is, therefore, an object of the present invention to provide a pressure tank of the above type where the taking on of odor by the water used is avoided and its manufacturing costs are reduced.
Another object of the present invention is to improve a pressure tank of the above type so as to eliminate rotting of the glass fiber wrapping.
A further object of the present invention is to provide a pressure tank of the foregoing character which is simple in construction and may be economically fabricated.
A still further object of the present invention is to provide a pressure tank, as described, which may be easily maintained in service and which has a substantially long service life.